Method for glazing leather



3 1947- c. D. KNOWL'IIJON ET AL 2,433,459

METHOD FOR GLAZING LEATHER Filed Sept. 5, 194a 34 fizz/enters I Cutler'flffnou/lton Dal/id Edgar Zr Attonef Patented Dec. 30, 1947 METHGD FOR GLAZING LEATHER Cutler D. Knowlton, Rockport, and David Edgar,

Lynn, Mass, assignors to United Shoe Maehinery Corporation, Flemington, N. J., a corporation of New Jersey Application September 5, 1946, Serial No. 694,946

3 Claims.

This invention relates to methods for operating upon work pieces such as tanned hides and skins to glaze the same. The present application presents a method which is an improvement over that disclosed in our Patent No. 2,398,835, granted on April 23, 1946.

Authorities in the leather industry differ greatly as to what constitutes correct glazing but it is generally agreed that the finish of properly glazed leather must be such as to be fast and must hold even after boarding or graining. The work also must not be burned or scorched by excess heat and the grain must lie fiat. Some desire the grain to be flattened down so that it is almost impossible to distinguish it. Others say the grain must be flat but also visible. Some say there should be a high gloss. Others desire very little, if any, gloss. It suffices, herein, to state that glazing is much more than mere polishing. The oils in the leather are afiected and the effect on th leather is more permanent.

In securing the desired results it has been customary to use machines having a glass member of limited dimensions arranged to be drawn progressively over successive paths on the surface of a Work piece. require a very considerable time and amount of labor adequately to treat any given work piece.

In applicants patent above mentioned a method and apparatus has been disclosed which very appreciably increases the rate at which leather may be glazed and it improves the quality of the product as judged by experienced tanners.

It is an object of this invention to provide an improved method for glazing leather which method will be more rapid, will require less power input, and improve the quality of work as compared with the method disclosed in the patent referred to as well as other prior methods.

As disclosed in our patent above referred to, we have found it feasible and highly advantageous to use a glazing roll having a surface layer of a material such as a dense wood, a wood impregnated with plastic material, paper or preferably a thermosetting plastic material, all of these being characterized as having a thermal conductivity substantially below that of glass. This can be done by making such roll of a relatively large diameter as compared with glazing members heretofore used and of such length as to be capable of treating the entire width of a work piece in a single passage through the machine. With such large diameter and with continuous treatment of an entire work piece, the surface layer of the glazing roll does not become highly heated Such machines and methods as an extensive cooling period is provided as the roll rotates before any given part of the surface of the roll repeats contact with the work piece. To insure that such glazing roll will not be overheated there is preferably (but not necessarily) provided a cooling system in the form of means for circulating air about said roll, all this being taught in the patent.

In a preferred construction, as used in the patented method and in the method of this invention, the glazing roll is made of a cylindrical layer of Textolite which is a phenolic resin of the Bakelite type superposed upon a paper base su-' perposed on a metal shaft, the Textolite being especially suitable because of its durability and resistance to high temperatures as well as its relatively very low thermal conductivity. Other suitable thermosetting compounds are phenol-v furfural, urea-formaldehyde, and phenol-formaldehyde. All glazing rolls made of these substances are preferably driven at substantial speed to glaze work pieces while the latter are backed by some work supporting surface which surface may be of felt or analogous material to facilitate feeding and to provide for varying thicknesses in different portions of a. skin.

As the method of the present application may be carried out by the apparatus slightly changed from that disclosed in the patent referred to, a description of the apparatus is herein curtailed and given with only that amount of detail which is necessary to describe the new method. and the driving mechanism for securing the proper directions of rotation of the machine parts for carrying out the method.

The important aspects of the invention will now be described in detail in the specification and then pointed out more particularly in the claims.

In the drawings,

Fig. 1 is a side view of an apparatus by the use of which the method of the present invention may be conveniently practiced, parts of the apparatus having been broken away for clarity; and

Fig. 2 is a front view, partly in section, showing more particularly means for giving the proper relative direction of rotation to the machine parts.

The machine shown in the drawing is provided with a platform l0 upon which is mounted a vertical frame l2 and a motor M. The frame 12 is fitted with bearings in which a work supporting roll I6, a work treating roll l8, and an idler gear l9 are journaled. The construction is such that,

the two rolls are resiliently brought into contact with each other and/or grasp between them a spread-out work piece of leather which may be extended to the bite. A platform or table 20 is supported at one side of the vertical frame l2 and the top surface thereof is in horizontal alinement with the bite of the rolls l6 and 18. An endless conveyor belt 22 is mounted to run on rollers 24, 26 and 28 and also around a portion of the work supporting roll IS. The roller 28 is journaled on suitable brackets one of which is shown in Fig. l. The work supporting roll l6 and the glazing roll (8 are arranged to be rotated in the same direction as shown by the arrows (Fig. 1)

by motor l4 and a conventional belt and gear drive. A gear 32 is keyed to the shaft of the roll I8 and drives the idler gear 19 which is in mesh with a gear 34 keyed to the shaft of the roll [6. The teeth of gears 19 and 34 are of such length that the driving relationship is retained despite the vertical movement permitted the roll [6 and the gear 34. The conveyor belt 22 is motivated by contact with the lower or work supporting roll i6 toreturn a treated work piece to the front of the machine below the table 29 upon which it was introduced for treating.

'A treadle and ratchet mechanism 5 is shown on the machine illustrated. Its; purpose is to serve as a quick release for safety of the operator or aid him in releasing and reintroducing a work piece which may have been folded during its first introduction. Such mechanism is not essential and forms no part of the present invention. 7 c The surface of the work support roll l6 may be covered with a layer 6 of felt, rubber, or some other material having a suitable coefficient of friction with leather to facilitate feeding of the work piece and compensate for varying thicknesses of work.

The glazing roll I8 may have a covering 8 .of Textolite, preferably, but it should be of some material, as previously referred to, having a smooth surface and being characterized by a thermal conductivity substantially below that of glass. Spiral grooves to aid in spreading the work piece may be out in the glazing roll covering.

In carrying out the method of the present invention the operator places a work piece on the table 20 spreading it out and presenting it to the bite of the two rolls [6 and Hi. The lower roll [6, having the cover 6, of felt or some analogous material and rotating slowly, tends to retain the Work piece in place upon its surface and to present the upper side of the work piece to the treatment of the rapidly rotating roll l8. It is to be noted that the work piece is fed in a direction contrary to the direction of motion of the contacting surface or layer 8 of roll I8. The bed roll I6 is urged upwardly against a narrow strip of the work piece at any given instant and, in the illustrated machine this is performed by springs with a requisite pressure to effect glazing and this pressure, for any given type or class of work, is easily determined.

The work piece, as it is treated by the glazing roll, passes downwardly and between the conveyor belt 22 and the roll I6 and emerges beneath the table 20 for removal by the sole operator of the machine.

The method is such that a narrow strip of the relatively slow moving work piece is presented to the glazing roll l8 for treatment at any given instant and the rapidly moving surface of the glazing roll l8 moves in a direction opposite to that of the work piece feed. In carrying out this method, work-has been produced which either cannot be distinguished from work carefully treated by old methods of glazing or it is superior thereto. The method herein disclosed is superior to the method of the patent referred to in several aspects. It was believed that the directions of rotation of the work supporting roll and the treating or glazing roll should be as taught in the patent and that a reversal of the direction of rotation for the roll l8 would be inadvisable as feeding of the work piece would be prevented. It was found, however, that if the roll l8 be rotated to present its surface layer 8 in an action against the direction of feed, the feeding of the work piece is facilitated, the glazing roll tends to remove possible wrinkles in the Work piece, the work piece smoothly and steadily is retained by the work supporting roll 16, and the R. P. M. of the glazing roll I8 is substantially reduced to save power input. It has been found that in treating a work piece of extended length the temperature ofthe glazing roll surface (as indicated by a thermo-couple touching the surface close to the bite of the rolls) sometimes rises as high as 170 F. but does not approach the danger point which may be 350 F. and at which point the leather is likely to be damaged. When the temperature rises to 170 F. for a long work piece, it immediately drops back to approximately 140 F. prior to the reception of the next work piece to the bite of the rolls.

The uniformity of finish imparted to the leather surface by the present method has proved to be excellent. and wrinkles are eliminated to a large extent. Considered from a broad viewpoint, the general quality of the work more than meets the tests that are commercially given to a glazing finish.

Having fully described our invention, what we claimas new and desire to secure by Letters Patent of the United States is:

1. A method for glazing a Work piece of tanned hide or skin which comprises slowly feeding a spread-out work piece in one direction, rapidly moving in the opposite direction a firm smooth surface of material characterized by a thermal conductivity substantially below that of glass, with only a narrow strip of the work piece in contact with the said smooth surface at any given instant, and pressing said strip against said surface to secure the glazing effect.

2. A method for glazing a work piece such as a tanned hide or skin which comprises slowly feeding a. spread-out work piece in one direction through the bite between a narrow work supporting surface and a rapidly moving smooth surface of thermosetting material of low thermal conductivity selected from a group consisting of phenol-formaldehyde, phenol-furfural and ureaformaldehyde compounds, the said smooth surface moving in a direction opposite to that of feed.

3. A method for glazing a work piece such as a tanned hide or skin which comprises slowly feeding-in one direction a spread-out work piece through the bite between a narrow work supporting surface and a rapidly moving smooth surface of material characterized by a thermal conductivity substantially below that of glass, the said smooth surface moving in a direction opposite to that of feed.

CUTLER D. KNOWLTON. DAVID EDGAR. 

